The overarching goal of the The Harvard Medical School Fellowship in Pediatric Gastroenterology and Nutrition is to train future physician-scientists in Pediatric Gastroenterology for original investigation in fields related to digestive diseases of infancy, childhood, and adult life. We offer a curriculum in basic or disease- oriented research, and another in clinical or patient-oriented research. The Basic Research training program focuses on three related fields in intestinal and hepatic biology and disease: 1) epithelial cell and developmental biology, 2) innate and acquired mucosal immunology, and 3) intestinal epithelial-microbial cross-talk and pathogenesis. The Clinical and Translational research training program focuses on: 1) intestinal and nutritional epidemiology, 2) bioinformatics, genomics, outcomes research, and 3) clinical studies including translational research in basic pharmacology of novel therapeutics. The program provides an in depth comprehensive scientific experience for each trainee in a research group at the forefront of its field. Eight postdoctoral positions are requested for 2-3 years of research training. Forty-three core reseach faculty support this effort. Training faculty are drawn from all Harvard Affiliated Hospitals and Research Institutes, the Harvard Medical School, and the Harvard School of Public Health. Opportunities for cross- fertilization are abundant. The Program Director is Dr. Wayne I. Lencer, Associate Professor of Pediatrics, Harvard Medical School, a widely respected investigator and mentor. A Scholarship Oversight Committee is assembled for each trainee to provide mentoring in scientific and career development. Didactic course work is required for both basic and clinical research training tracks and supplemented with relevant seminars and journal clubs, a course in the responsible conduct of research, and a bi-annual research retreat. Trainees in clinical research must obtain a Master's Degree in Medical Science or Public Heath (MMSc or MPH), both from the Harvard School of Public Health. Integration of training with the candidates' future goals in academic medicine, a strong focus on original research, and strong mentoring in science and career development are essential features of the program